/*
 * Copyright (c) 2012, Georgia Tech Research Corporation
 * All rights reserved.
 *
 * Author: Tobias Kunz <tobias@gatech.edu>
 * Date: 05/2012
 *
 * Humanoid Robotics Lab      Georgia Institute of Technology
 * Director: Mike Stilman     http://www.golems.org
 *
 * Algorithm details and publications:
 * http://www.golems.org/node/1570
 *
 * This file is provided under the following "BSD-style" License:
 *   Redistribution and use in source and binary forms, with or
 *   without modification, are permitted provided that the following
 *   conditions are met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *   CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 *   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 *   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 *   AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *   POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "../VirtualRobot.h"
#include <Eigen/Core>
#include "Path.h"

namespace VirtualRobot
{
    /**
     * @brief Implementation of paper:
     * Tobias Kunz and Mike Stilman
     * Time-Optimal Trajectory Generation for Path Following with Bounded Acceleration and Velocity
     * Robotics: Science and Systems. 2012.
     */
    class VIRTUAL_ROBOT_IMPORT_EXPORT TimeOptimalTrajectory
    {
    public:
        // Generates a time-optimal trajectory
        TimeOptimalTrajectory(const Path &path, const Eigen::VectorXd &maxVelocity, const Eigen::VectorXd &maxAcceleration, double timeStep = 0.001);

        ~TimeOptimalTrajectory(void);

        // Call this method after constructing the object to make sure the trajectory generation succeeded without errors.
        // If this method returns false, all other methods have undefined behavior.
        bool isValid() const;

        // Returns the optimal duration of the trajectory
        double getDuration() const;

        // Return the position/configuration or velocity vector of the robot for a given point in time within the trajectory.
        Eigen::VectorXd getPosition(double time) const;
        Eigen::VectorXd getVelocity(double time) const;

        // Outputs the phase trajectory and the velocity limit curve in 2 files for debugging purposes.
        void outputPhasePlaneTrajectory() const;

    private:
        struct TimeOptimalTrajectoryStep {
            TimeOptimalTrajectoryStep() {}
            TimeOptimalTrajectoryStep(double pathPos, double pathVel) :
                pathPos(pathPos),
                pathVel(pathVel)
            {}
            double pathPos;
            double pathVel;
            double time;
        };

        bool getNextSwitchingPoint(double pathPos, TimeOptimalTrajectoryStep &nextSwitchingPoint, double &beforeAcceleration, double &afterAcceleration);
        bool getNextAccelerationSwitchingPoint(double pathPos, TimeOptimalTrajectoryStep &nextSwitchingPoint, double &beforeAcceleration, double &afterAcceleration);
        bool getNextVelocitySwitchingPoint(double pathPos, TimeOptimalTrajectoryStep &nextSwitchingPoint, double &beforeAcceleration, double &afterAcceleration);
        bool integrateForward(std::list<TimeOptimalTrajectoryStep> &trajectory, double acceleration);
        void integrateBackward(std::list<TimeOptimalTrajectoryStep> &startTrajectory, double pathPos, double pathVel, double acceleration);
        double getMinMaxPathAcceleration(double pathPosition, double pathVelocity, bool max);
        double getMinMaxPhaseSlope(double pathPosition, double pathVelocity, bool max);
        double getAccelerationMaxPathVelocity(double pathPos) const;
        double getVelocityMaxPathVelocity(double pathPos) const;
        double getAccelerationMaxPathVelocityDeriv(double pathPos);
        double getVelocityMaxPathVelocityDeriv(double pathPos);

        std::list<TimeOptimalTrajectoryStep>::const_iterator getTrajectorySegment(double time) const;

        Path path;
        Eigen::VectorXd maxVelocity;
        Eigen::VectorXd maxAcceleration;
        unsigned int n;
        bool valid;
        std::list<TimeOptimalTrajectoryStep> trajectory;
        std::list<TimeOptimalTrajectoryStep> endTrajectory; // non-empty only if the trajectory generation failed.

        static const double eps;
        const double timeStep;

        mutable double cachedTime;
        mutable std::list<TimeOptimalTrajectoryStep>::const_iterator cachedTrajectorySegment;
    };
}

